LIQUID 4He ADSORBED FILMS ON VERY ATTRACTIVE SUBSTRATES

Abstract

Adsorbed films of liquid 4 He are analized, in the framework of Density functionals Theories (DF). In these systems, when the substrate becomes increasingly attractive, the thin films of 4 He approaches the quasi-bidimensional limit. We study this strongly attractive substrate regime with two DF, the Orsay-Trento (OT) and a recent Hybrid proposal (Hyb), focusing in the energy behavior. It is showed that OT does not reproduce the correct limiting energy curve, and it implies that this functional could not provide reliable results for very strongly attractive substrates like Graphite (Gr). In other hand, with the Hyb DF, the correct energy behavior is found for the adsorption energy of 4 He on Gr. These results show that OT should not be applied to quasi 2D (confinement) situations, and that Hyb DF provides a much more realistic description.